Substances can be classified as elements, compounds or mixtures.
- chromatography
- crystallisation
- distillation
- filtration
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Substances can be classified as elements, compounds or mixtures.
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This question is about mixtures and compounds.
|
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chromatography | crystallisation | evaporation |
filtration | fractional distillation | simple distillation |
Use words from the box to answer these questions.
(3)
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The box lists some substances. Choose substances from the box to answer these questions.
Each substance may be used once, more than once or not at all.
air | bromine | carbon | copper | glucose |
nitrogen | oxygen | sulfur | water |
(1)
(1)
(1)
(1)
(1)
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A student does a chromatography experiment using ink 1, ink 2, and three known dyes A, B and C. The student uses water as the solvent.
The diagram shows the student’s chromatogram.
(1)
(3)
Rf value = ...............................................
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This question is about chromatography.
Two students carry out separate chromatography experiments to find the Rf values for five different food dyes, A, B, C, D and E.
Dye | Student 1 Rf value | Student 2 Rf value |
A | 0.45 | 0.45 |
B | 0.63 | 0.64 |
C | 0.00 | 0.00 |
D | 0.83 | 1.20 |
E | 0.30 | 0.30 |
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This question is about elements, compounds and mixtures.
air bromine magnesium neon sodium chloride sulfur |
(1)
(1)
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Substances can be classified as elements, mixtures or compounds.
☐ | A | 1 | |
☐ | B | 2 | |
☐ | C | 3 | |
☐ | D | 4 |
[1]
☐ | A | 1 and 2 | |
☐ | B | 2 and 3 | |
☐ | C | 1 and 3 | |
☐ | D | 3 and 4 |
[1]
☐ | A | increasing mass number | |
☐ | B | Increasing number of neutrons | |
☐ | C | increasing number of protons | |
☐ | D | increasing reactivity |
[1]
☐ | A | electrons in outer shell | |
☐ | B | electron shells | |
☐ | C | neutrons | |
☐ | D | protons |
[1]
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The diagram below represents a sample of air:
What correctly describes this sample of air?
(1)
☐ | A | an element |
☐ | B | a compound |
☐ | C | a mixture of elements |
☐ | D | a mixture of compounds |
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A student uses this apparatus to investigate the colours in four different inks, A, B, C and D.
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This question is about the separation of mixtures.
crystallisation | filtration | fractional distillation | simple distillation |
(4)
Separation | Method |
insoluble solid from a liquid | |
pure water from a solution | |
liquid from a mixture of liquids with different boiling points | |
soluble solid from a solution |
(2)
(2)
(2)
distance = .............................................................. mm
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The diagram shows four pieces of apparatus for separating mixtures:
Which one would be most suitable for separating a mixture of alcohol and water?
(1)
☐ | A | |
☐ | B | |
☐ | C | |
☐ | D |
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A student uses paper chromatography in an experiment to separate the dyes in four different food colourings, E, F, G and H.
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This question is about soluble and insoluble compounds.
A precipitate is an insoluble compound formed when solutions of soluble compounds react after mixing.
☐ | A | 1 and 2 only | |
☐ | B | 2 and 3 only | |
☐ | C | 1 and 3 only | |
☐ | D | 1, 2 and 3 |
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A student obtained the following chromatogram for substance A.
Determine the Rf value of substance A.
(1)
☐ | A | 0.66 |
☐ | B | 0.26 |
☐ | C | 0.35 |
☐ | D | 0.43 |
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A student uses paper chromatography to investigate the dyes in five different inks, V, W, X, Y and Z.
This is what she uses.
(4)
[2]
(2)
(2)
(2)
(3)
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A student is given a mixture of salt solution and sand. She wants to obtain pure water from the mixture.
☐ | A | crystallisation |
☐ | B | filtration |
☐ | C | fractional distillation |
☐ | D | simple distillation |
(3)
X ......................................................................................................................
Y ......................................................................................................................
Z ......................................................................................................................
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A student set up the following apparatus to investigate the colours in three different food colourings.
What are the stationary and mobile phases for this experiment?
(1)
☐ | A | stationary: chromatography paper | mobile: water | |
☐ | B | stationary: beaker | mobile: start line | |
☐ | C | stationary: water | mobile: food colourings | |
☐ | D | stationary: start line | mobile: chromatography paper |
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In a chromatography experiment a student uses samples of three pure food dyes, blue (B), red (R) and yellow (Y). He also uses samples of four unknown substances, S, T, U and V. The student puts a small drop of each substance on the pencil line. The diagram shows the student’s chromatogram at the end of the experiment.
☐ | A | substance S | |
☐ | B | substance T | |
☐ | C | substance U | |
☐ | D | substance V |
(3)
Rf = ..............................................................
(1)
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A student is given a mixture of salt solution and sand. She wants to separate the sand from the salt solution.
Which method of separation should she use?
(1)
☐ | A | crystallisation |
☐ | B | filtration |
☐ | C | fractional distillation |
☐ | D | simple distillation |
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Chromatography is used to analyse mixtures.
A student does a chromatography experiment to analyse the composition of green food colouring in sweets.
She places four known dyes, A, B, C and D, and the green food colouring on chromatography paper.
The diagram shows the student’s apparatus at the start of her experiment.
The diagram shows that the student makes two mistakes when setting up her apparatus.
[3]
[1]
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A salt can be made by reacting an acid with an insoluble base.
A student has a sample of copper‘(Il) oxide.
The student uses this method.
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The table gives information about some lead compounds.
Compound | Formula | Appearance | Solubility in water |
lead(II) oxide | PbO | yellow solid | insoluble |
lead(IV) oxide | PbO2 | brown solid | insoluble |
red lead oxide | Pb3O4 | red solid | insoluble |
lead(II) nitrate | Pb(NO3)2 | white solid | soluble |
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